Technical Field
The disclosure relates to a printing apparatus, and more particularly, relates to a three-dimensional printing apparatus.
Description of Related Art
In recent years, with advancement of technologies, many different methods have been proposed to build physical three-dimensional (3D) models by using an additive manufacturing technology for building a model layer by layer. Generally, in the additive manufacturing technology, design data of a 3D model built by computer-aided design (CAD) software or the like is transformed into a plurality of thin (quasi-two-dimensional) cross-sectional layers stacked over one another in succession. Recently, many technical means for forming the thin cross-sectional layers are also proposed. For example, a printing unit of the three-dimensional printing apparatus is usually moved above a platform in an XY plane with reference to space coordinates XYZ constructed according to the design data of the 3D model in order to form a correct shape of the cross-sectional layer by using a building material. Thereafter, by driving the printing unit to move along a Z axis layer by layer, the cross-sectional layers may be gradually stacked and cured layer by layer to form the 3D object.
Some three-dimensional printing apparatuses use a cylinder to fill the building material, and dispose the cylinder in the printing unit with a pressing head, such that the building material may be extruded to the outside by the pressing header. The cylinder is usually disposed on a bracket of the printing unit corresponding to the pressing head. When the building material in the cylinder is used up or when other cylinders are to be replaced based on demands, a replacement of the cylinder is usually performed manually. This replacement increases an operating cost for the three-dimensional printing apparatus as well as a required time for building the 3D object.